Decreased ecto-NTPDase1/CD39 activity leads to desensitization of P2 purinoceptors regulating tonus of corpora cavernosa in impotent men with endothelial dysfunction

Vascular responses to adenine nucleotides in human corpora cavernosa from men with vasculogenic erectile dysfunction were investigated. We also evaluated the catabolism of extracellular adenine nucleotides to probe its relevance to vascular hemodynamics in impotent men. Human corpora cavernosa have high NTPDase1/CD39 activity, converting ATP directly into AMP, without significant ADP formation. Extracellular ATP hydrolysis is slower in impotent patients. Adenine nucleotides have dual roles on phenylephrine-contracted strips of corpora cavernosa operated by P2X-contractant and P2Y-relaxant receptors. Prolonged exposure to endogenous ATP related to decreased NTPDase1/CD39 activity leads to P2-purinoceptor desensitization in impotent men. Shutting down ATP signaling in vasculogenic impotent men may represent a defense mechanism for preventing purinergic overstimulation.     

Increased expression of arginase II in human diabetic corpus cavernosum: in diabetic-associated erectile dysfunction

Nitric oxide (NO) is the principal mediator of penile erection. NO is synthesized by nitric oxide synthase (NOS). It has been well documented that the major causative factor contributing to erectile dysfunction in diabetic patients is the reduction in the amount of NO synthesis in the corpora cavernosa of the penis resulting in alterations of normal penile homeostasis. Arginase is an enzyme that shares a common substrate with NOS, thus arginase may downregulate NO production by competing with NOS for this substrate, l-arginine. The purpose of the present study was to compare arginase gene expression, protein levels, and enzyme activity in diabetic human cavernosal tissue. When compared to normal human cavernosal tissue, diabetic corpus cavernosum from humans with erectile dysfunction had higher levels of arginase II protein, gene expression, and enzyme activity. In contrast, gene expression and protein levels of arginase I were not significantly different in diabetic cavernosal tissue when compared to control tissue. The reduced ability of diabetic tissue to convert l-arginine to l-citrulline via nitric oxide synthase was reversed by the selective inhibition of arginase by 2(S)-amino-6-boronohexanoic acid (ABH). These data suggest that the increased expression of arginase II in diabetic cavernosal tissue may contribute to the erectile dysfunction associated with this common disease process and may play a role in other manifestations of diabetic disease in which nitric oxide production is decreased.     

Androgen-dependent nitric oxide release in rat penis correlates with levels of constitutive nitric oxide synthase isoenzymes.

Androgens are known to influence penile erection and nitric oxide synthase (NOS) activity in cavernosal tissue homogenates. The present study was an assessment of the effects of castration and androgen replacement on the in vivo release of nitric oxide (NO), and of the simultaneously recorded intracavernosal pressure (ICP) changes elicited by electrostimulation of the cavernosal nerves (SCN) in the anesthetized rat. The extracellular levels of NO in the corpora were monitored electrochemically using porphyrin microsensors. The content of NOS isoenzymes in corporal homogenates was determined by immunoblotting. The responses of castrated rats with or without testosterone (T) implants were compared to those of intact animals. Castration virtually abolished both the NO and the ICP responses to SCN. There was a concomitant significant decrease in the content of both the neuronal (nNOS) and the endothelial (eNOS) isoenzymes in the cavernosal tissue. All these effects of castration were prevented by T replacement. The NO response to SCN was positively correlated with the levels of nNOS and eNOS, especially when the values of the two isoforms were added (r = 0.71, P < 0.001). These data suggest that the facilitatory action of androgens on penile erection involves the up-regulation of both constitutive NOS isoenzymes in the corpora cavernosa.     

Changes in mating behavior, erectile function, and nitric oxide levels in penile corpora cavernosa in streptozotocin-diabetic rats.

This study assessed whether the in vivo production of nitric oxide (NO) in the penis is impaired in experimental diabetes and whether this phenomenon can be explained by abnormal levels of NO synthase isoenzymes and/or plasma androgens. Adult male Sprague-Dawley rats were injected with streptozotocin (STZ) (40 mg/kg, i.p.) or vehicle. One half of the STZ-treated animals received daily insulin replacement. Twelve weeks later, the animals were tested for mating behavior and erectile reflexes. They were then anesthetized with urethane (1 g/kg), and the NO levels in their corpora cavernosa were monitored electrochemically with porphyrin microsensors before and after electrostimulation of the cavernous nerve. The intracavernous pressure (ICP) was measured simultaneously. The diabetic animals had substantial impairment in the mating and erectile reflexes tests, decreased basal and stimulated NO levels in the corpora, and a reduced ICP response to cavernous nerve stimulation. Insulin replacement fully reversed the effects of diabetes on the mating reflexes, the basal NO signals, and the ICP responses to electrical field stimulation and partially restored the stimulated NO release. Neither diabetes nor diabetes with insulin treatment had significant effects on serum testosterone levels or NOS isoform (nNOS, eNOS, and iNOS) protein content in penile homogenates, indicating that the changes found in erectile function were independent of such variables. These results also suggest that the diabetes-induced reduction in corporeal NO levels could be mainly due to the lack of some essential cofactors for NOS activity rather than to changes in the amount of enzyme proteins.     

Persistent activation of autophagy in kidney tubular cells promotes renal interstitial fibrosis during unilateral ureteral obstruction

Renal fibrosis is the final, common pathway of end-stage renal disease. Whether and how autophagy contributes to renal fibrosis remains unclear. Here we first detected persistent autophagy in kidney proximal tubules in the renal fibrosis model of unilateral ureteral obstruction (UUO) in mice. UUO-associated fibrosis was suppressed by pharmacological inhibitors of autophagy and also by kidney proximal tubule-specific knockout of autophagy-related 7 (PT-Atg7 KO). Consistently, proliferation and activation of fibroblasts, as indicated by the expression of ACTA2/α-smooth muscle actin and VIM (vimentin), was inhibited in PT-Atg7 KO mice, so was the accumulation of extracellular matrix components including FN1 (fibronectin 1) and collagen fibrils. Tubular atrophy, apoptosis, nephron loss, and interstitial macrophage infiltration were all inhibited in these mice. Moreover, these mice showed a specific suppression of the expression of a profibrotic factor FGF2 (fibroblast growth factor 2). In vitro, TGFB1 (transforming growth factor β 1) induced autophagy, apoptosis, and FN1 accumulation in primary proximal tubular cells. Inhibition of autophagy suppressed FN1 accumulation and apoptosis, while enhancement of autophagy increased TGFB1-induced-cell death. These results suggest that persistent activation of autophagy in kidney proximal tubules promotes renal interstitial fibrosis during UUO. The profibrotic function of autophagy is related to the regulation on tubular cell death, interstitial inflammation, and the production of profibrotic factors.     

Erectile Dysfunction and Essential Hypertension: The Same Aging-related Disorder?

An erection is a mechanical event dependent primarily on corporeal vascular dynamics wherein arterial inflow and storage of blood within the corpora is greater than the egress of blood from the corpora. The most common cause of erectile dysfunction (ED) is the inability of the corporal tissue to store the blood within the corporal sinusoids once inflow into the corpora begins. This failure to store is primarily due to a corporal smooth muscle dysfunction and, in most men, is most likely an aging-related occurrence. Because the corporal smooth muscle is embryologically and physiologically indistinguishable from the smooth muscle within our arterial system, the authors hypothesize that the aging-related dysfunction that occurs within the penis also occurs within the arterial system, and that this smooth muscle dysfunction within the arterial media is most likely the cause of what is called essential hypertension. This panvascular smooth muscle myopathy could explain why hypertension is the most common comorbidity associated with ED and appears to indicate that both ED and essential hypertension are the same disorder, albeit in two different organ systems.Key words: Erection, Endothelium, Smooth muscle, HypertensionAlmost all men recognize at some time in their lives that their erectile function begins to change. For most men, the ability to attain and maintain an erection during the teenage years is second nature. However, by the time men hit the fourth and fifth decade of life, many have recognized that their erectile function has changed, and the ability to maintain an erection during sex has diminished; the refractory period, the time in between erectile events, begins to increase. Although men in their teenage years and young adult lives are able to have multiple erectile events at will, this ability begins to fade as aging sets in. Because the ability to maintain an erection is directly related to the function of the corporal smooth muscle, this increase in the refractory period is a clinical sign that the smooth muscle of the corpora is likely becoming dysfunctional. This review highlights what we know about the corporal smooth muscle cell and demonstrates that what occurs to the corporal smooth muscle cell also occurs to its embryologic sibling, the smooth muscle cell within the media of the peripheral vascular system. As a result of this relationship, changes in the function of the penis can reflect changes in the vascular system.     

Lipopolysaccharide mediates hepatic stellate cell activation by regulating autophagy and retinoic acid signaling

Bacterial translocation and lipopolysaccharide (LPS) leakage occur at a very early stage of liver fibrosis in animal models. We studied the role of LPS in hepatic stellate cell (HSC) activation and the underlying mechanisms in vitro and in vivo. Herein, we demonstrated that LPS treatment led to a dramatic increase in autophagosome formation and autophagic flux in LX-2 cells and HSCs, which was mediated through the AKT-MTOR and AMPK-ULK1 pathway. LPS significantly decreased the lipid content, including the lipid droplet (LD) number and lipid staining area in HSCs; pretreatment with macroautophagy/autophagy inhibitors or silencing ATG5 attenuated this decrease. Furthermore, lipophagy was induced by LPS through the autophagy-lysosomal pathway in LX-2 cells and HSCs. Additionally, LPS-induced autophagy further reduced retinoic acid (RA) signaling, as demonstrated by a decrease in the intracellular RA level and Rar target genes, resulting in the downregulation of Bambi and promoting the sensitization of the HSC's fibrosis response to TGFB. Compared with CCl₄ injection alone, CCl₄ plus LPS injection exaggerated liver fibrosis in mice, as demonstrated by increased Col1a1 (collagen, type I, α 1), Acta2, Tgfb and Timp1 mRNA expression, ACTA2/α-SMA and COL1A1 protein expression, and Sirius Red staining area, which could be attenuated by injection of an autophagy inhibitor. LPS also reduced lipid content in HSCs in vivo, with this change being attenuated by chloroquine (CQ) administration. In conclusion, LPS-induced autophagy resulted in LD loss, RA signaling dysfunction, and downregulation of the TGFB pseudoreceptor Bambi, thus sensitizing HSCs to TGFB signaling.     

Gene therapy of erectile dysfunction in the rat with penile neuronal nitric oxide synthase

Gene transfer to the penile corpora cavernosa of constructs of the inducible and endothelial nitric oxide synthase (NOS) cDNAs ameliorates erectile dysfunction in aged rats. In this study, we investigated whether the neuronal NOS (nNOS) variant responsible for erection, penile nNOS (PnNOS), can exert a similar effect, and whether the combination of electroporation with a helper-dependent adenovirus (AdV) improves gene transfer. PnNOS and beta-galactosidase cDNAs were cloned in plasmid (pCMV-PnNOS; pCMV-beta-gal) and "gutless" AdV (AdV-CMV-PnNOS; AdV-CMV-beta-gal) vectors, and injected into the penis of adult (beta-gal) or aged (PnNOS) rats, with or without electroporation. Penile erection was measured at different times after PnNOS cDNA injection, by electrical field stimulation of the cavernosal nerve. The expression of beta-galactosidase or PnNOS was estimated in penile tissue by either histochemistry and luminometry or Western blot, and the effects of AdV-CMV-PnNOS on mRNA expression were examined by a DNA microarray. We found that electroporation increased pCMV-beta-gal uptake, and its expression was detectable at 56 days. In the aged rats treated with pCMV-PnNOS and electroporation, the maximal intracavernosal:mean arterial pressure ratios were elevated for 11 and 18 days when compared with those in controls. Electroporation intensified penile uptake of as few as 10(6) viral particles (vp) of AdV-CMV-beta-gal, and with 10(7) vp beta-galactosidase was still detectable at 60 days. Electroporated AdV-CMV-PnNOS (10(7) vp) was effective at 18 days in stimulating the erection of aged rats, without inducing the expression of cytotoxic genes. In conclusion, intracavernosal gene therapy with PnNOS cDNA corrected the aging-related erectile dysfunction for at least 18 days when given by electroporation in a helper-dependent AdV at low viral loads.     

Gene therapy of erectile dysfunction in the rat with penile neuronal nitric oxide synthase

Gene transfer to the penile corpora cavernosa of constructs of the inducible and endothelial nitric oxide synthase (NOS) cDNAs ameliorates erectile dysfunction in aged rats. In this study, we investigated whether the neuronal NOS (nNOS) variant responsible for erection, penile nNOS (PnNOS), can exert a similar effect, and whether the combination of electroporation with a helper-dependent adenovirus (AdV) improves gene transfer. PnNOS and beta-galactosidase cDNAs were cloned in plasmid (pCMV-PnNOS; pCMV-beta-gal) and "gutless" AdV (AdV-CMV-PnNOS; AdV-CMV-beta-gal) vectors, and injected into the penis of adult (beta-gal) or aged (PnNOS) rats, with or without electroporation. Penile erection was measured at different times after PnNOS cDNA injection, by electrical field stimulation of the cavernosal nerve. The expression of beta-galactosidase or PnNOS was estimated in penile tissue by either histochemistry and luminometry or Western blot, and the effects of AdV-CMV-PnNOS on mRNA expression were examined by a DNA microarray. We found that electroporation increased pCMV-beta-gal uptake, and its expression was detectable at 56 days. In the aged rats treated with pCMV-PnNOS and electroporation, the maximal intracavernosal:mean arterial pressure ratios were elevated for 11 and 18 days when compared with those in controls. Electroporation intensified penile uptake of as few as 10(6) viral particles (vp) of AdV-CMV-beta-gal, and with 10(7) vp beta-galactosidase was still detectable at 60 days. Electroporated AdV-CMV-PnNOS (10(7) vp) was effective at 18 days in stimulating the erection of aged rats, without inducing the expression of cytotoxic genes. In conclusion, intracavernosal gene therapy with PnNOS cDNA corrected the aging-related erectile dysfunction for at least 18 days when given by electroporation in a helper-dependent AdV at low viral loads.     

Future strategies for treating erectile dysfunction

Erectile dysfunction affects over half of all men between 50 and 70 years of age, and by the age of 40, about 40% of men may suffer from some form of erectile dysfunction. Many disease states, such as diabetes, hypertension, depression, and vascular disease, are associated with the condition, which may occur many years prior to the onset of these disorders. The phenomenal success of sildenafil in improving erections in men with erectile dysfunction is due to the fact that the drug, as a phosphodiesterase inhibitor, improves the relaxation of smooth muscle cells, which become dysfunctional with the aging process. However, not everyone responds to this medication, mainly because the efficacy of the drug is directly dependent on the release of nitric oxide from the nerve terminals of the cavernosal nerve, and this may become defective with aging/certain disease states. The goal of gene therapy for organic impotence is to allow the patient to sustain physiologically elicited erections without resorting to pharmacological treatment immediately prior to the sexual act. Experimental efforts in gene therapy for erectile dysfunction are likely to continue intensively in a series of directions, some specific to the nature of the selected gene to be manipulated or the physiology of the corpora cavernosa itself, and others extrapolatable from the advancement of gene therapy in general.     

Isolation and passage of muscle-derived stem cells from the rat penile corpora cavernosa and induction of differentiation into smooth muscle cells

This study treated the isolation and passage of muscle-derived stem cells (MDSCs) from rat penile corpora cavernosa, detection of stem cell marker expression, observation of their self-renewal and continuous proliferation, and demonstration of their potential to differentiate into smooth muscle cells in co-culture. Muscle-derived stem cells from the rat penile corpora cavernosa were isolated and purified. The expression of stem cell markers Sca-1 and desmin was detected in PP6 cells, thus confirming that the main components of PP6 cells are MDSCs. The expression of Sca-1 and desmin occurred both in PP6 cells and cells at passages 3, 6, and 8, and there was no significant decrease in the expression level with increasing passage number. The growth curves indicated that the cell doubling time was approximately 48 h. The cells entered the stationary phase after approximately 7 days of culture. The proliferative activity of the cells at passage 8 remained unchanged. After 2 days of co-culture with smooth muscle cells, the DAPI-labeled MDSCs tended to exhibit smooth muscle cell morphology and expression of α-SMA was detected. MDSCs exist in the rat penile corpora cavernosa and possess the potential to differentiate into smooth muscle cells. This discovery serves as the basis in view of the potential use of endogenous stem cells for the treatment of erectile dysfunction (ED).     

Cell density and proliferation modulate collagen synthesis and procollagen mRNA levels in arterial smooth muscle cells.

Collagen synthesis and procollagen mRNA levels were determined and compared in (1) sparse, rapidly proliferating smooth muscle cells (SMC); (2) postconfluent, density-arrested SMC; and (3) sparse, nonproliferating (mitogen-deprived) rabbit arterial SMC. Collagen synthesis per SMC was decreased by 70% in postconfluent versus proliferating cells. However, relative collagen synthesis, expressed as the percentage of total protein synthesis, increased from 3.7% in sparse cultures to approximately 7% in postconfluent cultures. Slot blot analyses demonstrated that the relative steady state alpha 1(I) and alpha 1(III) procollagen mRNA levels were also increased in postconfluent cultures when compared to sparse cultures. As with collagen synthesis per cell, the mRNA levels per cell for types I and III procollagen in postconfluent cells, determined by densitometry of blots, were likewise approximately half that found in sparse, proliferating cells. In a separate study to determine if cell-cell contact was necessary for eliciting these changes in collagen synthesis, we determined collagen synthesis in mitogen-deprived and proliferating SMC cultures at low density. Mitogen-deprived cultures synthesized only 10% the amount of collagen produced (per cell) by proliferating cultures in 10% fetal bovine serum. Relative collagen synthesis in proliferating and nonproliferating cultures was 5.0 and 8.3%, respectively. These results demonstrate elevated collagen synthesis, per cell, by proliferating cultures compared with nonproliferating cultures, regardless of whether cells were rendered quiescent by density arrest or by mitogen deprivation. Results also suggest a pretranslational mechanism for the regulation of collagen synthesis in rabbit aortic smooth muscle cells.     

Altered Sonic hedgehog signaling is associated with morphological abnormalities in the penis of the BB/WOR diabetic rat

Erectile dysfunction (ED) is a common and debilitating pathological development that affects up to 75% of diabetic males. Neural stimulation is a crucial aspect of the normal erection process. Nerve injury causes ED and disrupts signaling of the Sonic hedgehog (Shh) cascade in the smooth muscle of the corpora cavernosa. Shh and targets of its signaling establish normal corpora cavernosal morphology during postnatal differentiation of the penis and regulate homeostasis in the adult. Interruption of the Shh cascade in the smooth muscle of the corpora cavernosa results in extensive changes in corpora cavernosal morphology that lead to ED. Our hypothesis is that the neuropathy observed in diabetics causes morphological changes in the corpora cavernosa of the penis that result in ED. Disruption of the Shh cascade may be involved in this process. We tested this hypothesis by examining morphological changes in the penis, altered gene and protein expression, apoptosis, and bromodeoxyuridine incorporation in the BB/WOR rat model of diabetes. Extensive smooth muscle and endothelial degradation was observed in the corpora cavernosa of diabetic penes. This degradation accompanied profound ED, significantly decreased Shh protein in the smooth muscle of the corpora cavernosa, and increased penile Shh RNA expression in the intact penis (nerves, corpora, and urethra). Localization and expression of Shh targets were also disrupted in the corpora cavernosa. Increasing our understanding of the molecular mechanisms that regulate Shh signaling may provide valuable insight into improving treatment options for diabetic impotence.     

MicroRNA-146b-5p promotes atrial fibrosis in atrial fibrillation by repressing TIMP4

Alteration of tissue inhibitors of matrix metalloproteinases (TIMP)/matrix metalloproteinases (MMP) associated with collagen upregulation has an important role in sustained atrial fibrillation (AF). The expression of miR-146b-5p, whose the targeted gene is TIMPs, is upregulated in atrial cardiomyocytes during AF. This study was to determine whether miR-146b-5p could regulate the gene expression of TIMP4 and the contribution of miRNA to atrial fibrosis in AF. Collagen synthesis was observed after miR-146b-5p transfection in human induced pluripotent stem cell-derived atrial cardiomyocytes (hiPSC-aCMs)-fibroblast co-culture cellular model in vitro. Furthermore, a myocardial infarction (MI) mouse model was used to confirm the protective effect of miR-146b-5p downregulation on atrial fibrosis. The expression level of miR-146b-5p was upregulated, while the expression level of TIMP4 was downregulated in the fibrotic atrium of canine with AF. miR-146b-5p transfection in hiPSC-aCMs-fibroblast co-culture cellular model increased collagen synthesis by regulating TIMP4/MMP9 mediated extracellular matrix proteins synthesis. The inhibition of miR-146b-5p expression reduced the phenotypes of cardiac fibrosis in the MI mouse model. Fibrotic marker MMP9, TGFB1 and COL1A1 were significantly downregulated, while TIMP4 was significantly upregulated (at both mRNA and protein levels) by miR-146b-5p inhibition in cardiomyocytes of MI heart. We concluded that collagen fibres were accumulated in extracellular space on miR-146b-5p overexpressed co-culture cellular model. Moreover, the cardiac fibrosis induced by MI was attenuated in antagomiR-146 treated mice by increasing the expression of TIMP4, which indicated that the inhibition of miR-146b-5p might become an effective therapeutic approach for preventing atrial fibrosis.     

Cardiovascular risk factors, erection disorders and endothelium dysfunction

Upon sexual stimulation, penile erection, occurring in response to the activation of pro-erectile autonomic pathways, is greatly dependent on adequate inflow of blood to the erectile tissue and requires coordinated arterial endothelium-dependent vasodilatation and sinusoidal endothelium-dependent corporal smooth muscle relaxation. Nitric oxide (NO) is the principal peripheral pro-erectile neurotransmitter which is released by both non-adrenergic, non-cholinergic neurons and the sinusoidal endothelium to relax corporal smooth muscle through the cGMP pathway. Any factors modifying the basal corporal tone, the arterial inflow of blood to the corpora, the synthesis/release of neurogenic or endothelial NO are prime suspects for being involved in the pathophysiology of erectile dysfunction (ED). In fact, conditions associated with altered endothelial function, such as ageing, hypertension, hypercholesterolemia and diabetes, may, by changing the balance between contractant and relaxant factors, cause circulatory and structural changes in penile tissues, resulting in arterial insufficiency and defect in smooth muscle relaxation and thus, ED. There is increasing evidence to suggest that ED is predominantly a vascular disease and may even be a marker for occult cardiovascular disease. Recent results illustrating the importance of endothelial dysfunction in the pathophysiology of different forms of experimental ED are discussed. These pathways may represent new potential treatment targets.     

-Arginine and phosphodiesterase (PDE) inhibitors counteract fibrosis in the Peyronie’s fibrotic plaque and related fibroblast cultures

Inducible nitric oxide synthase (iNOS) is expressed in both the fibrotic plaque of Peyronie's disease (PD) in the human, and in the PD-like plaque elicited by injection of TGFbeta1 into the penile tunica albuginea (TA) of the rat. Long-term inhibition of iNOS activity, presumably by blocking nitric oxide (NO)- and cGMP-mediated effects triggered by iNOS expression, exacerbates tissue fibrosis through an increase in: (a) collagen synthesis, (b) levels of reactive oxygen species (ROS), and (c) the differentiation of fibroblasts into myofibroblasts. We have now investigated whether: (a) phosphodiesterase (PDE) isoforms, that regulate the interplay of cGMP and cAMP pathways, are expressed in both the human and rat TA; and (b) L-arginine, that stimulates NOS activity and hence NO synthesis, and PDE inhibitors, that increase the levels of cGMP and/or cAMP, can inhibit collagen synthesis and induce fibroblast/myofibroblast apoptosis, thus acting as antifibrotic agents. We have found by immunohistochemistry, RT/PCR, and Western blot that PDE5A-3 and PDE4A, B, and D variants are indeed expressed in human and rat normal TA and PD plaque tissue, as well as in their respective fibroblast cultures. As expected, in the PD fibroblast cultures, pentoxifylline (non-specific cAMP-PDE inhibitor) increased cAMP levels without affecting cGMP levels, whereas sildenafil (PDE5A inhibitor) raised cGMP levels. Both agents and L-arginine reduced the expression of collagen I (but not collagen III) and the myofibroblast marker, alpha-smooth muscle actin, as determined by immunocytochemistry and quantitative image analysis. These effects were mimicked by incubation with 8-Br-cGMP, which in addition increased apoptosis, as measured by TUNEL. When L-arginine (2.25 g/kg/day), pentoxifylline (10 mg/kg/day), or sildenafil (10 mg/kg/day) was given individually in the drinking water for 45 days to rats with a PD-like plaque induced by TGF beta1, each treatment resulted in a 80-95% reduction in both plaque size and in the collagen/fibroblast ratio, as determined by Masson trichrome staining. Both sildenafil and pentoxiphylline stimulated fibroblast apoptosis within the TA. Our results support the hypothesis that the increase in NO and/or cGMP/cAMP levels by long-term administration of nitrergic agents or inhibitors of PDE, may be effective in reversing the fibrosis of PD, and more speculatively, other fibrotic conditions.     

Decreased Ecto-Ntpdase1/Cd39 Activity Leads to Desensitization of P2 Purinoceptors Regulating Tonus of Corpora Cavernosa in Impotent Men with Endothelial Dysfunction

Vascular responses to adenine nucleotides in human corpora cavernosa from men with vasculogenic erectile dysfunction were investigated. We also evaluated the catabolism of extracellular adenine nucleotides to probe its relevance to vascular hemodynamics in impotent men. Human corpora cavernosa have high NTPDase1/CD39 activity, converting ATP directly into AMP, without significant ADP formation. Extracellular ATP hydrolysis is slower in impotent patients. Adenine nucleotides have dual roles on phenylephrine-contracted strips of corpora cavernosa operated by P2X-contractant and P2Y-relaxant receptors. Prolonged exposure to endogenous ATP related to decreased NTPDase1/CD39 activity leads to P2-purinoceptor desensitization in impotent men. Shutting down ATP signaling in vasculogenic impotent men may represent a defense mechanism for preventing purinergic overstimulation.     

Priapisme veineux: traitement et pronostic fonctionnel. A propos de 26 cas

Introduction

Priapism is a prolonged, painful and persistent erection, unrelated to sexual stimulation. The management of priapism is complex and requires various medical or surgical treatments. The authors review the aetiology, treatment and outcome of priapism.

Material and methods

26 cases of low-flow priapism were collected over a period of 23 years (1985–2007), corresponding to 22 adults and 4 children (average age: 32 years) with various types of priapism. The time to appropriate management after onset of priapism varied according to the aetiology and the time to consultation (range: 16 hours to 15 days).

Results

Complete and persistent detumescence for the first 24 hours was obtained in 84% of cases, sometimes with multiple successive procedures. No case of early recurrence was observed. 21 patients were regularly followed for a period of 3 months to 10 years (mean follow-up: 2 years). There were 9 (42.9%) successes (recovery of normal erectile function), 4 partial results (19%) and 9 (30.1%) failures (complete erectile dysfunction).

Conclusion

Low-flow priapism must be considered to be a serious andrological emergency. Medical treatment can be effective in early forms, but surgery must not be delayed to prevent permanent erectile dysfunction secondary to extensive corpora cavernosa fibrosis.     

Subcellular localization and regulation of type-1C and type-5 phosphodiesterases

We investigated the subcellular localization of PDE5 in in vitro human myometrial cells. We demonstrated for the first time that PDE5 is localized in discrete cytoplasmic foci and vesicular compartments corresponding to centrosomes. We also found that PDE5 intracellular localization is not cell- or species-specific, as it is conserved in different animal and human cells. PDE5 protein levels are strongly regulated by the mitotic activity of the smooth muscle cells (SMCs), as they were increased in quiescent, contractile myometrial cultures, and conditions in which proliferation was inhibited. In contrast, PDE1C levels decreased in all conditions that inhibited proliferation. This mirrored the enzymatic activity of both PDE5 and PDE1C. Increasing cGMP intracellular levels by dbcGMP or sildenafil treatments did not block proliferation, while dbcAMP inhibited myometrial cell proliferation. Together, these results suggest that PDE5 regulation of cGMP intracellular levels is not involved in the control of SMC cycle progression, but may represent one of the markers of the contractile phenotype.     

Systematic analyses identify the anti-fibrotic role of lncRNA TP53TG1 in IPF

Long non-coding RNA (lncRNA) was reported to be a critical regulator of cellular homeostasis, but poorly understood in idiopathic pulmonary fibrosis (IPF). Here, we systematically identified a crucial lncRNA, p53-induced long non-coding RNA TP53 target 1 (TP53TG1), which was the dysregulated hub gene in IPF regulatory network and one of the top degree genes and down-regulated in IPF-drived fibroblasts. Functional experiments revealed that overexpression of TP53TG1 attenuated the increased expression of fibronectin 1 (Fn1), Collagen 1α1, Collagen 3α1, ACTA2 mRNA, Fn1, and Collagen I protein level, excessive fibroblasts proliferation, migration and differentiation induced by TGF-β1 in MRC-5 as well as PMLFs. In vivo assays identified that forced expression of TP53TG1 by adeno-associated virus 5 (AAV5) not only prevented BLM-induced experimental fibrosis but also reversed established lung fibrosis in the murine model. Mechanistically, TP53TG1 was found to bind to amount of tight junction proteins. Importantly, we found that TP53TG1 binds to the Myosin Heavy Chain 9 (MYH9) to inhibit its protein expression and thus the MYH9-mediated activation of fibroblasts. Collectively, we identified the TP53TG1 as a master suppressor of fibroblast activation and IPF, which could be a potential hub for targeting treatment of the disease.Subject terms: Long non-coding RNAs, Respiratory tract diseases